Cleaning compositions and methods of using the same

ABSTRACT

Cleaning compositions are disclosed that economically and effectively remove a variety of marking materials from many coated or uncoated substrate surfaces. The compositions contain a terpene compound, a pyrrolidone compound, an emulsifying surfactant, and water, the compositions being in the form of a microemulsion. Also disclosed are methods of cleaning marked surfaces with the microemulsion compositions.

BACKGROUND OF THE INVENTION

This invention relates generally to cleaning compositions and methods.More particularly, this invention relates to microemulsion cleaningcompositions that effectively and economically remove markings fromsurfaces and to methods of using the microemulsion compositions. Thecompositions and methods are effective to remove a wide variety ofmarking materials from many substrate surfaces without damage to oralteration of the surfaces, their coatings, or adjacent areas. Whilethis invention is subject to a wide range of applications, it isespecially suited for removing graffiti and will be describedparticularly in that connection.

The removal of markings from various surfaces has been of interest for along time. The restoration of the original appearance of inadvertentlyor intentionally marked surfaces can present considerable problems. Morerecently, there has been increased concern in removing undesiredmarkings known as graffiti, which are defacements in the form of wordsor figures on walls and other surfaces of public and private places. Inpart due to proliferation and availability of aerosol paint sprays, inkmarking devices, and other marking means, it has proven difficult toavoid defacement of surfaces by graffiti.

Removing graffiti is difficult because of the great variety of markingmaterials, many of which are inherently difficult to remove. Thesemarking materials include paints, inks, marking pens, ballpoint pens,lipstick, shoe polish, nail polish, permanent markers, chalk, andcrayon.

Consistent removal of markings made by these materials is complicated bythe variety of substrate surfaces on which the markings are made. Thesesurfaces include acrylic, aluminum, anodized aluminum, brick, ceramics,concrete, Corian™, enameled surfaces, formica, glass, grout, marble,Marlite™, metals, plastic, polycarbonate (Lexan™), plexiglass,polyethylene, polysulfone, quarry tile, stainless steel, stone, tile,and wood. Some surfaces are porous, and the markings may penetrate thepores, making removal even more difficult. In addition, metals and othersubstrate surfaces may have a coating or other finish which has beendefaced by the markings.

Graffiti has become prevalent in many public and private institutions,buildings, and places such as restaurants, schools, school buses,automobiles, trucks, trains, libraries, rest rooms, and other placesaccessible to the public at large. Graffiti is also problematic in openareas and on public works, such as support walls, piers, bridges,retaining walls, sound barriers, exterior building walls, sculptures,and other structures found in parks, highways, and open spaces.

Perhaps the most common way of removing graffiti is to repaint or recoatthe surface. This approach is perhaps the least effective and leasteconomical. Repainting a surface is costly and labor intensive. Itrequires using a paint capable of covering and masking the graffitiwithout the graffiti bleeding through the overcoat. Often several coatsare required. Moreover, this method is often undesirable because itdestroys the desired original finish of many surfaces.

Other methods for removing graffiti have included sandblasting,hydrosanding, or hydroblasting. These methods also are costly andbecause of their abrasive nature often damage the substrate surface orits coating, making it porous and rough. This etching or scoring of thesurfaces or their coatings creates a degree of porosity that helps holdgraffiti applied later to the surface, as well as to areas in closeproximity to the originally marked area. Like repainting, these methodscannot be used for surfaces where maintaining an original finishcharacteristic is desired. Further, sandblasting emits potentiallycarcinogenic siliceous particles into the air.

Still other methods and compositions for removing graffiti involve theuse of chemical removing agents, such as acids or caustics. These agentsalso frequently damage or destroy the defaced surfaces. For example,chemical agents are known to etch, fog, or melt many common surfaces.Use of these compositions often must be for limited periods of time ornot over an extended period of time to avoid permanent damage to thesurface being cleaned. Highly acid and caustic compositions also presentan unreasonable health and safety risk to the persons using or otherwiseexposed to these compositions.

Still other widely used cleaning compositions include a volatile organicchemical solvent base, particularly halogenated solvents such asmethylene chloride. The high volatility of these solvents leads to highevaporation losses, risks ignition of the organic vapors, and causescontamination of the environment. These compositions also are highlyobjectionable due to their extreme toxicity, particularly frominhalation or exposure. Many chlorinated hydrocarbons, includingmethylene chloride, are suspected carcinogens. The hazardous nature ofthese chemicals is well-documented in the literature, and it is clearthat a safe, non-toxic alternative is required.

Accordingly, there is a great need for cleaning compositions that areeconomical, that effectively remove a wide variety of marking materialsfrom many surfaces with minimal damage to the substrate surfaces ortheir protective coatings, and that minimize safety and environmentalhazards.

SUMMARY OF THE INVENTION

The present invention is directed to improved cleaning compositions andmethods that effectively and economically remove a wide variety ofmarking materials from a wide variety of uncoated and coated substratesurfaces with no or negligible effect to the substrates or theircoatings. The present compositions are easily applied to substratesurfaces, fast acting, and easily rinsed or otherwise removed from thesubstrate surfaces with water or an aqueous solution, thus avoiding theoften difficult labor associated with prior compositions and methods.Further, the present compositions are relatively non-toxic and present areduced health risk from exposure to the skin, eyes, and mucousmembranes. The compositions of this invention also are relativelynon-volatile, reducing the safety hazards associated with volatilevapors.

Additional features and advantages of the invention will be set forth inthe description that follows and, in part, will be apparent from thedescription or may be learned by practice of the invention. Theobjectives and other advantages of this invention will be realized andattained by the compositions and methods particularly pointed out in thefollowing written description, examples, and claims.

To achieve these and other advantages, and in accordance with thepurpose of this invention as embodied and described herein, theinvention is a microemulsion cleaning composition that includes aterpene compound, a pyrrolidone compound, a surfactant effective to forma microemulsion, and water.

In another aspect, the present invention is a method for removingmarking materials from a substrate surface that includes applying to thesurface a microemulsion cleaning composition that includes a terpenecompound, a pyrrolidone compound, a surfactant effective to form amicroemulsion, and water. In this aspect, the invention further includescontacting the marking material with the composition for a sufficienttime for the composition to solubilize the marking material, followed byremoving the composition and the marking material with water or anaqueous solution.

It is to be understood that the foregoing general description and thefollowing detailed description are exemplary, explanatory, and intendedto provide further explanations of the invention as claimed.

DETAILED DESCRIPTION OF THE INVENTION

The compositions of the present invention contain a terpene compound,preferably about 1% to about 60% by weight, more preferably about 5% toabout 40% by weight, and even more preferably about 10% to about 20% byweight, of a terpene or terpene compound. As used herein, the termsterpene and terpene compound refer to a class of acyclic and cyclicunsaturated compounds derived from the isoprene molecule and having atleast 10 carbon atoms. However, terpenes that find use in the presentinvention also include terpene alcohols and aldehydes as well asunsaturated terpene hydrocarbons. Any number of compounds, includingcombinations of terpenes, can be used in the present invention.

Terpene compounds for use in the present include alpha-pinene,beta-pinene, citronellal, citronellol, 3,7-dimethyl-octanol, d-limonene,delta 3-carine, gamma-terpinene, hydroxycitronellal, linalool,p-menthane, terpinerol, and tetrahydrolinalool, among others, withcyclic terpenes being preferred. Other preferred terpenes for use incompositions of the present invention include Solvenol™ 226 terpene byHercules, Inc. and Glidsol™ 190, Limonene™ 125, Limonene™ 135, andLimonene™ 145 terpenes by Glidco Organics Corp. Solvenol™ 226 terpene byHercules, Inc. is a terpene solvent mixture having as its majorcomponents by weight 34% to 40% trans-p-menthane, 12% to 15% p-cymene,10% to 15% dipentene, 8% to 10% alpha-pinene, 6% to 10% beta-pinene, 3%to 4% camphene, and 2% to 5% alpha-terpinene. Glidsol™ 190, Limonene™125, Limonene™ 135, and Limonene™ 145 terpenes sold by Glidco OrganicsCorporation are mixtures of various isomers of terpene (C10)hydrocarbons, primarily isomers of p-menthadiene. In addition theGlidsol™ 190 terpene contains aromatic terpene hydrocarbons.

Compositions of the present invention also contain a pyrrolidonecompound, preferably about 1% to about 60% by weight, more preferablyabout 5% to about 40%, and even more preferably about 10% to about 20%by weight, of a pyrrolidone compound. As used herein, the termpyrrolidone compound refers to a class of cyclic compounds including andderived from 2-pyrrolidinone, 3-pyrrolidinone, or pyrrolidine,unsubstituted or substituted at the ring nitrogen or one or more of thering carbons.

As described and claimed herein, the nitrogen of the pyrrolidone ringmay be unsubstituted or substituted with alkyl groups. A preferredpyrrolidone compound for this invention is N-methylpyrrolidone, a highlypolar, water-miscible solvent that is miscible with many conventionalorganic solvents. Other solvents similar to N-methylpyrrolidone insolubility and solvent power may be used in the present invention, andmay include structural analogues of N-methylpyrrolidone, for exampleN-ethylpyrrolidone and N-propylpyrrolidone, among other solvents.However, as the number of carbon atoms within the N-substituted moietyincreases beyond 3 (propyl), water miscibility of the pyrrolidonedecreases. In addition, such substitution may affect the solvent powerof the pyrrolidone compound used.

In addition to nitrogen substitution, the carbon atoms of thepyrrolidone ring may also be substituted. These substituted compoundsare less preferred for use in this invention than N-methylpyrrolidonebecause of cost and the reduced polarity caused by their substitutions.For example, N,5-dimethyl-2-pyrrolidone and 3,3-dimethyl-2-pyrrolidonemay be used in the present invention, but are less preferred than isN-methylpyrrolidone.

The 2-keto group of N-methylpyrrolidone is not a requirement for thepyrrolidone compound of the present invention and certain pyrrolidoneanalogs, for example, N,2-dimethylpyrrolidine, 2,4-dimethylpyrrolidine,2,5-dimethylpyrrolidine, and N-methylpyrrolidine, among others, may beused in this invention. Pyrrolidone and pyrrolidine compounds that maybe used in the present invention may be less polar thanN-methylpyrrolidone, necessitating adjustment to the amount and type ofsurfactant and/or terpene compound used.

The compositions of the present invention also include a surfactanteffective to form a microemulsion, preferably about 1% to about 35% byweight, more preferably about 5% to about 20% by weight, and even morepreferably about 10% to about 15% by weight, of a surfactant effectiveto form a microemulsion, selected from nonionic, cationic, anionic, oramphoteric surfactants. As used herein, the phrase "surfactant effectiveto form a microemulsion" refers to at least one such nonionic, cationic,anionic, or amphoteric surfactant.

Examples of nonionic surfactants that can be employed are alkoxylatedalkyl phenols, amides, amines, ethoxylated or propoxylated higheraliphatic alcohols, and sulphonamides. These well known surfactantsinclude sorbitan esters of C₁₀ to C₂₂ fatty acids, polyoxyethylenesorbitan esters of C₁₀ to C₂₂ fatty acids, polyoxyethylene sorbitolesters of C₁₀ to C₂₂ fatty acids, polyoxyethylene derivatives of C₆ toC₂₀ fatty phenols, and polyoxyethylene condensates of C₁₀ to C₂₂ fattyacids or fatty alcohols. Polyoxyethylene and polyoxypropylene analogs ofthe above surfactants also can be used in the present invention.Preferred nonionic surfactants for use in this invention are ShellNeodol™ 91-6 and Shell Neodol™ 91-2.5 surfactants. Neodol™ 91-6surfactant is a polyethylene glycol ether of a mixture of syntheticC9-11 fatty alcohols with an average of 6 moles of ethylene oxide.Neodol™ 91-2.5 surfactant is a polyethylene glycol ether of a mixture ofsynthetic C9-11 fatty alcohols with an average of 3 moles of ethyleneoxide.

Other suitable nonionic surfactants include sorbitol monolauratepropylene oxide condensates, sorbitol monomyristate propylene oxidecondensates, sorbitol monostearate propylene oxide condensates, dodecylphenol propylene oxide condensates, myristyl phenol propylene oxidecondensates, octylphenyl propylene oxide condensates, nonlyphenylpropylene oxide condensates, stearyl phenol propylene oxide condensates,lauryl alcohol propylene oxide condensates stearyl alcohol propyleneoxide condensates, secondary alcohol propylene oxide condensates such asC₁₄ -C₁₅ secondary alcohols condensed with propylene oxide, sorbitantristearate condensed with propylene oxide, sorbitan trioleate condensedwith propylene oxide, and sorbitan trioleate.

Cationic surfactants useful in this invention include, e.g., thequaternary ammonium surfactants such as C₁₀ to C₂₂ fatty ammoniumcompounds having 10 to 22 carbon atoms, C₁₀ to C₂₂ fatty morpholineoxides, propylene oxide condensates of C₁₀ to C₂₂ fatty acid monoestersof glycerins, the mono- or diethanol amides of C₁₀ to C₂₂ fatty acids,and alkoxylated siloxane surfactants containing propylene oxide unitsand/or propylene oxide units. As is known in the surfactant art, thecounter ion for quaternary ammonium surfactants is usually a halide,sulfate, or methylsulfate, the chlorides being the most commonindustrially available compounds.

Other suitable cationic surfactants suitable for use in the presentinvention include straight chain alkyl fatty amines, quaternary ammoniumsalts, alkyl-substituted quaternary ammonium salts,alkylaryl-substituted quaternary ammonium salts, quaternaryimidazolinium salts, amine oxides, fatty amine oxides, tri-fatty amineoxides, tri-quaternary phosphate esters, amphoglycinate phosphates,amine acetates, long chain amines and their salts, diamines and theirsalts, polyamines and their salts, polyoxyethylenated long chain amines,and quaternized polyoxyethylenated long chain amines.

Specific cationic surfactants useful in the present invention includedecyl dimethyl amino oxide, coco amido dimethyl amine oxide, trimethyldodceyl ammonium chloride, and trimethyl stearyl ammonium methylsulfate.Particularly preferred cationic surfactants include the surfactant soldunder the trademark Q-17-2™ and the AO-3,8™ surfactant by the ExxonChemical Company, Varisoft™ 222 and Arosurf™ TA-100 surfactants by theWitco Chemical Company, and Ninox L™ surfactant by the Stepan ChemicalCompany. Q-17-2™ surfactant by the Exxon Chemical Company is a 75% byweight aqueous solution of isotridecyloxypropyl dihydroxyethyl methylammonium chloride. The Exxon AO-3,8™ surfactant is a proprietarytertiary eight-carbon amine oxide. The Varisoft™ 222 surfactant is adiamidoamine-based quaternary with a formula of methyl bis (tallowamidoethyl) 2-hydroxyethyl ammonium methyl sulfate. The Arosurf™ TA-100surfactant is a dialkyl dimethyl quaternary with the chemicalcomposition of distearyl dimethyl ammonium chloride. The Ninox-L™surfactant is a lauryl dimethylamine oxide.

Anionic surfactants useful in this invention generally include alkalimetal, ammonium and magnesium salts of alpha olefin sulfonates, alkylsulfonates, alkyl aryl sulfonates, alkyl aryl ether sulfates, alkylether sulfates, sulfated alcohol ethoxylates, taurates, petroleumsulfonates, alkyl napthalene sulfonates, alkyl sarcosinates and thealkyl sulfosuccinates.

Specific anionic surfactants useful in this invention include sodiumlauryl sulfonate, ammonium lauryl sulfonate, dodecyl benzene sulfonate,sodium lauryl ether sulfate, diethanolamine lauryl sulfate, ammoniumsalts of sulfated alcohol ethoxylates, sodium cocoyl isethionate, sodiumN-methyl-N-oleoyl taurate, sodium N-methyl-N-cocyl taurate,triethanolamine lauryl sulfate, disodium monooleamide PEG-2sulfosuccinate, petroleum sulfonates sodium salt, alkyl napthalenesodium sulfonates, sodium lauroyl sarcosinate, and sodium alkylsulfosuccinate. Other useful anionic surfactants include sodium orpotassium dodecyl sulfate, sodium trioleate, sodium or potassium stearylsulfate, sodium or potassium dodecyl benzene sulfonate, sodium orpotassium stearyl sulfonate, triethanol amine salt of dodecyl sulfate,sodium laurate, sodium or potassium myristate, and sodium or potassiumstearate.

Amphoteric surfactants useful in this invention generally includebetaines, sultaines, imidazoline derivatives and the like. Specificamphoteric surfactants useful in this invention includericinoleamidopropyl betaine, cocamidopropyl betaine, stearyl betaine,stearyl amphocarboxy glycinate, sodium lauraminopropionate,cocoamidopropyl hydroxy sultaine, disodium lauryliminodipropionate,tallowiminodipropionate, cocoamphocarboxy glycinate, cocoimidazolinecarboxylate, lauric imidazoline mono-carboxylate, lauric imidazolinedicarboxylate, lauric myristic betain, cocoamidosulfobetaine,alkylamidophospho betain and the like. Other useful amphotericsurfactants include decyl amino betaine; coco amido sulfobetaine, oleylamido betaine, coco imidazoline, coco sulfoimidazoline, cetylimidazoline, 1-hydroxyethyl-2-heptadecenyl imidazoline, 1-hydroxyethyl-2mixed heptadecenyl heptadecadienyl imidazoline, and n-coco morpholineoxide. Preferred amphoteric surfactants include Miranol™ FBS surfactantby Rhone-Poulenc and Mackalene™ 316 surfactant by the McIntyre ChemicalCompany. The Miranol™ FBS surfactant is a 39% by weight aqueous solutionof disodium cocoampho dipropionate. The Mackalene™ 316 surfactant is astearamidopropyl dimethylamine lactate.

The foregoing compounds have been described with particular reference tofatty derivatives. It is the fatty moiety that usually forms thelipophilic moiety. A common fatty group is an alkyl group of natural orsynthetic origin. In most instances, the alkyl group may be replaced bythe corresponding ethylenically saturated group having one or moreethylene linkages such as commonly occur in nature. Common unsaturatedgroups are oleyl, linoleyl, decenyl, hexadecenyl, dodecenyl, etc. Inappropriate cases, as known in the art, the alkyl group may be cyclic,i.e., cycloalkyls, or may be straight or branched chain.

Any combination of nonionic, cationic, anionic, or amphotericsurfactants can be used in the present invention. It may be preferablein certain embodiments of the present invention to include a mixture ofsurfactants. In all embodiments, the surfactant selected is effective toform a microemulsion in the final composition.

The compositions of this invention further include water, preferably atleast about 20%, more preferably about 25% to about 60% by weight, andeven more preferably about 40% to about 50% by weight, of water. Wateris critical to the formation of the microemulsion compositions of thisinvention. Further, water increases the solubility of the presentcompositions and thus enhances their removal after application to amarked substrate. It is to be understood by one of ordinary skill in theart that the other components, particularly the emulsifying surfactant,may require adjustment to accommodate a given water concentration and toresult in formation of a microemulsion composition.

Compositions of the present invention may also include a solventextender or a combination of solvent extenders, preferably about 5% toabout 20% by weight, and more preferably about 10% to 15% by weight, ofa solvent extender or combination of solvent extenders. The solventextender in the present invention functions either or both to enhancesolubility characteristics or to raise the flash point of thecompositions. In addition, the solvent extenders used in the presentinvention may be useful for forming the microemulsions of the presentinvention.

The microemulsion cleaning compositions of the present invention have aflash point of at least about 105° F. by virtue of the amount and typeof solvent extender added to the compositions. Preferred solventextenders for use in the present invention have a flash point of atleast about 150° F. Typical solvent extenders for use in the presentinvention include small chain alcohols, e.g. ethanol and isopropanol,alkylene carbonates, e.g. ethylene carbonate, propylene carbonate andbutylene carbonate, and glycols and glycol ethers.

Glycols useful as solvent extenders in the compositions of the presentinvention include ethylene glycol, propylene glycol and butylene glycol,among others. Useful glycol ethers includediethyleneglycolmonobutylether, diethyleneglycolmonoethylether,diethyleneglycolmonohexylether, diethyleneglycolmonomethylether.diethyleneglycolmonopropylether, dipropyleneglycolmonobutylether,dipropyleneglycolmonomethylether, dipropyleneglycolmonopropylether,ethoxylpropyleneglycolmonobutylether, ethyleneglycolmonoethylether,ethyleneglycolmonohexylether, ethyleneglycolmonomethylether,ethyleneglycolmonobutylether, ethyleneglycolmonopropylether,propyleneglycolmonobutylether, propyleneglycolmonomethylether,propyleneglycolmonopropylether, propyleneglycolmono-t-butylether,triethyleneglycolmonoethylether, triethyleneglycolmonomethylether,triethyleneglycolmonopropylether, and tripropyleneglycolmonomethylether,among others. Preferred solvent extenders are propylene glycol, hexyleneglycol, and propylene glycol monomethyl ether because of their favorableflash points as well as their general safety and lack of toxicity.

The pH of the cleaning compositions of the present invention can varyfrom highly acidic to highly alkaline within the range of about 2.0 toabout 12.0. Preferred embodiments of the cleaning compositions of thepresent invention have a pH within the range of about 5.5 to about 8.0,preferably within the range of about 6.0 to about 8.0. Adjustment of pHin the present compositions to desired levels can be accomplished bymethods well known to the art, such as, for example, by addition ofalkali earth carbonates or hydroxides, or by addition of inorganic ororganic acids.

The preparation of the microemulsion compositions of the invention isnot critical, and the compositions of the invention are prepared easilyby any one of numerous methods known to those skilled in the art. Allthat is required is a suitable vessel to hold the components and asimple mixing means effective to bring the combined ingredients into amicroemulsion form. A suitable apparatus for preparing the compositionsof this invention would be a stainless steel tank furnished with aconventional, paddle-type mixer. Generally, the ingredients can be addedto the vessel in any order. Mixing should continue until the productbecomes a stable, clear microemulsion. The microemulsion compositions ofthe invention give rise to no separation, coalescence, crystallization,or sedimentation on storage.

To remove unwanted markings on smooth, non-porous surfaces, the presentcompositions are sprayed, brushed, or wiped onto the affected area. Apreferred method of application is a light spray. After application, thecleaning composition is allowed to stand at least several seconds topermit solubilization of the marking material. The composition andmarking material then are wiped or rinsed off with a dry or damp papertowel, cloth, or sponge, or by a stream or spray of water or otheraqueous solution. As used in describing and claiming the step ofremoving the compositions and marking material according to the methodsherein, the term water refers to both water and aqueous solutions. Toremove unwanted markings from porous surfaces, the present compositionsare applied in the manners described above, again, preferably by a lightspray. The compositions then preferably are brushed into the surface andallowed to stand for several seconds, followed by rinsing with a streamor spray of water or other aqueous solution.

EXAMPLES Graffiti Remover Formulas

In the following Examples 1-17, the compositions were prepared by addingthe ingredients in the order listed to a glass beaker equipped with amagnetic stirring bar. After each ingredient was added, the beakercontents were mixed thoroughly to form a uniform composition. In eachexample a microemulsion was obtained that was clear, fluid, and stablewhen tested under a temperature cycle of 25° F. to 120° F.

    ______________________________________                                        EXAMPLE 1                                                                     Ingredients           Concentration w/w %                                     ______________________________________                                        N-methylpyrrolidone   14.3                                                    Solvenol 226          14.3                                                    Propylene Glycol Monomethyl Ether                                                                   7.2                                                     Hexylene Glycol       5.1                                                     Q-17-2 ™           1.6                                                     Neodol ™ 91-2.5    6.2                                                     Neodol ™ 91-6      6.2                                                     H.sub.2 O             45.1                                                    ______________________________________                                        EXAMPLE 2                                                                     N-methylpyrrolidone   20.0                                                    Solvenol 226          20.0                                                    Propylene Glycol Monomethyl Ether                                                                   9.5                                                     Neodol ™ 91-6      0.5                                                     Triethanolamine       5.0                                                     Oleic Acid            10.0                                                    H.sub.2 O             35.0                                                    ______________________________________                                        EXAMPLE 3                                                                     N-methylpyrrolidone   19.0                                                    Solvenol 226          19.0                                                    Propylene Glycol Monomethyl Ether                                                                   9.5                                                     Q-17-2 ™           2.8                                                     Neodol ™ 91-2.5    8.1                                                     Neodol ™ 91-6      8.1                                                     H.sub.2 O             33.5                                                    ______________________________________                                        EXAMPLES     NO. 4   NO. 5     NO. 6 NO. 7                                    ______________________________________                                        N-methylpyrrolidone                                                                        14.8    13.9      13.3  13.4                                     Solvenol 226 14.8    13.9      13.3  13.4                                     Propylene Glycol                                                                           7.4      7.0       6.7  6.8                                      Monomethyl Ether                                                              Hexylene Glycol                                                                            5.3      4.9       4.7  4.8                                      Q-17-2 ™  0.5      0.5       1.5  --                                       Neodol ™ 91-2.5                                                                         5.3      4.1       4.6  9.6                                      Neodol ™ 91-6                                                                           5.3     12.1      13.9  9.6                                      H.sub.2 O    46.6    43.6      42.0  42.4                                     ______________________________________                                        EXAMPLES     NO. 8   NO. 9     NO. 10                                                                              NO. 11                                   ______________________________________                                        N-methylpyrrolidone                                                                        13.7    14.0      11.5  12.5                                     Solvenol 226 13.7    14.0      11.5  12.5                                     Propylene Glycol                                                                            6.9    7.0       5.8    6.3                                     Monomethyl Ether                                                              Hexylene Glycol                                                                             4.9    5.0       4.1    4.4                                     Q-17-2 ™  --      2.9       --    --                                       Neodol ™ 91-2.5                                                                          4.5    6.5       23.1  --                                       Neodol ™ 91-6                                                                           13.3    6.5       7.7   25.0                                     H.sub.2 O    43.0    44.1      36.3  39.3                                     ______________________________________                                        EXAMPLE 12                                                                    N-methylpyrrolidone   14.1                                                    Solvenol 226          14.1                                                    Propylene Glycol Monomethyl Ether                                                                   7.1                                                     Hexylene Glycol       5.0                                                     Arosurf ™ TA-100   1.6                                                     Neodol ™ 91-2.5    6.7                                                     Neodol ™ 91-6      6.7                                                     H.sub.2 O             44.7                                                    ______________________________________                                        EXAMPLE 13                                                                    N-methylpyrrolidone   14.3                                                    Solvenol 226          14.3                                                    Propylene Glycol Monomethyl Ether                                                                   7.2                                                     Hexylene Glycol       5.1                                                     Varisoft ™ 222     1.6                                                     Neodol ™ 91-2.5    3.7                                                     Neodol ™ 91-6      3.7                                                     H.sub.2 O             50.1                                                    ______________________________________                                        EXAMPLE 14                                                                    N-methylpyrrolidone   14.3                                                    Solvenol 226          14.3                                                    Propylene Glycol Monomethyl Ether                                                                   7.2                                                     Hexylene Glycol       5.1                                                     Mackalene ™ 316    1.6                                                     Neodol ™ 91-2.5    4.6                                                     Neodol ™ 91-6      4.6                                                     H.sub.2 O             48.3                                                    ______________________________________                                        EXAMPLE 15                                                                    N-methylpyrrolidone   14.3                                                    Solvenol 226          14.3                                                    Propylene Glycol Monomethyl Ether                                                                   7.2                                                     Hexylene Glycol       5.1                                                     Arosurf ™ TA 100   0.5                                                     Neodol ™ 91-2.5    5.0                                                     Neodol ™ 91-6      5.0                                                     H.sub.2 O             48.6                                                    ______________________________________                                        EXAMPLE 16                                                                    N-methylpyrrolidone   14.3                                                    Solvenol 226          14.3                                                    Propylene Glycol Monomethyl Ether                                                                   7.2                                                     Hexylene Glycol       5.1                                                     Ninox ™ L          1.6                                                     Neodol ™ 91-2.5    2.5                                                     Neodol ™ 91-6      2.5                                                     H.sub.2 O             52.5                                                    ______________________________________                                        EXAMPLE 17                                                                    N-methylpyrrolidone   14.3                                                    Solvenol 226          14.3                                                    Propylene Glycol Monomethyl Ether                                                                   7.2                                                     Hexylene Glycol       5.1                                                     Miranol ™ FBS      1.6                                                     Neodol ™ 91-2.5    2.8                                                     Neodol ™ 91-6      2.8                                                     H.sub.2 O             51.9                                                    ______________________________________                                    

EXAMPLE 18 Graffiti Remover Test--Performance and Effect on Surface

This table summarizes the performance and effect on substrate surface ofthe composition of Example 1 tested on a variety of marking materialsand substrates. The composition was used in accordance with the methodsdescribed above in the specification for use of the present compositionsto remove markings from porous and non-porous surfaces.

                  TABLE                                                           ______________________________________                                        Surface    Graffiti                 Effect on                                 Description                                                                              Type        Performance  Surface                                   ______________________________________                                        Painted dumpster                                                                         Red spray paint                                                                           Complete removal                                                                           Abrasion                                  Concrete wall                                                                            White spray paint                                                                         Only shadow left                                                                           Discolore                                 Brick wall White spray paint                                                                         Only shadow left                                                                           Discolore                                 Painted cement                                                                           Gray spray paint                                                                          Complete removal                                                                           None                                      Wallpaper  Blue pen    Complete removal                                                                           None                                      Grout lines                                                                              Ballpoint pen                                                                             Complete removal                                                                           None                                      Ceramic tiles                                                                            White marker                                                                              Complete removal                                                                           None                                      Quarry tile                                                                              Glue        Complete removal                                                                           None                                      Ceramic tile                                                                             Color markers                                                                             Complete removal                                                                           None                                      Marble store                                                                             Black marker                                                                              Complete removal                                                                           None                                      front                                                                         Table tops Various markers                                                                           Complete removal                                                                           None                                      Painted gate                                                                             Black spray paint                                                                         Only shadow left                                                                           None                                      Brick      Spray paint Only shadow left                                                                           None                                      Polished granite                                                                         Various markers                                                                           Complete removal                                                                           None                                      White sink Black marker                                                                              Complete removal                                                                           None                                      White wall Marker      Complete removal                                                                           None                                      Ceramic tile                                                                             Black marker                                                                              Complete removal                                                                           None                                      Table      Blue pen    Complete removal                                                                           None                                      Grout lines                                                                              Black marker                                                                              Complete removal                                                                           None                                      Air freshener                                                                            Marker      Complete removal                                                                           None                                      Painted door                                                                             Grey spray paint                                                                          Complete removal                                                                           None                                      Glass      Gold spray paint                                                                          Complete removal                                                                           None                                      Mirror     Black marker                                                                              Complete removal                                                                           None                                      Plastic seating                                                                          Silver marker                                                                             Complete removal                                                                           None                                      Aluminum window                                                                          Silver marker                                                                             Complete removal                                                                           None                                      frame                                                                         Porcelain sink                                                                           Blue marker Complete removal                                                                           None                                      Pay phone  Assortment  Complete removal                                                                           None                                      Polished marble                                                                          Black spray paint                                                                         No removal   None                                      Brick wall Dark spray paint                                                                          Only shadow left                                                                           None                                      Rest room wall                                                                           Black marker                                                                              Only shadow left                                                                           None                                      Glass door Black spray paint                                                                         Complete removal                                                                           None                                      Ceramic tiles                                                                            Blue marker Complete removal                                                                           None                                      Mirrors    Black marker                                                                              Complete removal                                                                           None                                      Seating    Black marker                                                                              Complete removal                                                                           None                                      Ceramic tile wall                                                                        White marker                                                                              Complete removal                                                                           None                                      Stainless door                                                                           Black marker                                                                              Complete removal                                                                           None                                      frame                                                                         Plastic air                                                                              Gold marker Complete removal                                                                           None                                      freshener                                                                     Brown painted                                                                            Black marker                                                                              Complete removal                                                                           None                                      surface                                                                       Chain link fence                                                                         Silver spray paint                                                                        Complete removal                                                                           None                                      Bathroom doors                                                                           Gold spray paint                                                                          Complete removal                                                                           None                                      Painted door                                                                             Black spray paint                                                                         Complete removal                                                                           None                                      Seating    Ballpoint pen                                                                             Complete removal                                                                           None                                      Brick wall Black marker                                                                              Complete removal                                                                           None                                      Brick wall Black marker                                                                              Only shadow left                                                                           None                                      Rest room wall                                                                           White marker                                                                              Complete removal                                                                           None                                      Quarry tile                                                                              Silver marker                                                                             Complete removal                                                                           None                                      baseboard                                                                     Brick wall Various paints                                                                            Complete removal                                                                           None                                      Wallpaper  Black marker                                                                              Only shadow left                                                                           None                                      Entryway frame                                                                           Marker      Complete removal                                                                           None                                      Baby changer                                                                             Black/green Only shadow left                                                                           None                                      table      marker                                                             Trash can  Spray paint Complete removal                                                                           None                                      Brick wall Black spray paint                                                                         Only shadow left                                                                           None                                      Block wall Black spray paint                                                                         No removal   None                                      Dumpster   Gold spray paint                                                                          Complete removal                                                                           None                                      Natural wood                                                                             Red spray paint                                                                           Slight removal                                                                             None                                      Pay phone booth                                                                          Black marker                                                                              Complete removal                                                                           None                                      Garbage pail                                                                             Red spray paint                                                                           Complete removal                                                                           None                                      Painted door                                                                             Black marker                                                                              Complete removal                                                                           Removed                                                                       paint                                     Painted metal                                                                            Brown spray Only shadow left                                                                           Removed                                   door       paint                    paint                                     Wallpaper  Black marker                                                                              Complete removal                                                                           Slight                                                                        abrasion                                  Painted door                                                                             Black marker                                                                              Cornplete removal                                                                          Softened                                                                      paint                                     ______________________________________                                    

It will be apparent to those skilled in the art that variousmodifications and variations can be made in the composition and methodof the present invention without departing from the spirit or scope ofthe invention. Thus, it is intended that the present invention cover themodifications and variations of this invention provided they come withinthe scope of the appended claims and their equivalents.

We claim:
 1. A microemulsion cleaning composition comprising:a. about 1% to about 60% by weight of a terpene compound; b. about 1% to about 60% by weight of a pyrrolidone compound; c. about 1% to about 35% by weight of a surfactant effective to form a microemulsion; d. 9.5% to about 20% by weight of a solvent extender selected from the group consisting of small chain alcohols, alkylene carbonates, ethylene glycol, propylene glycol, butylene glycol, hexylene glycol, diethyleneglycolmonobutylether, diethyleneglycolmonoethylether, diethyleneglycolmonohexylether, diethyleneglycolmonomethylether, diethyleneglycolmonopropylether, dipropyleneglycolmonobutylether, dipropyleneglycolmonomethylether, dipropyleneglycolmonopropylether, ethoxypropyleneglycolmonobutylether, ethyleneglycolmonoethylether, ethyleneglycolmonohexylether, ethyleneglycolmonomethylether, ethyleneglycolmonopropylether, propyleneglycolmonobutylether, propyleneglycolmonomethylether, propyleneglycolmonopropylether, propyleneglycolmono-t-butylether, triethyleneglycolmonoethylether, triethyleneglycolmonomethylether, triethyleneglycolmonopropylether, and tripropyleneglycolmonomethylether; and e. at least about 20% by weight water; said composition being in the form of a microemulsion.
 2. The microemulsion cleaning composition according to claim 1 comprising:a. about 5% to about 40% by weight of a terpene compound; b. about 5% to about 40% by weight of a pyrrolidone compound; c. about 5% to about 20% by weight of a surfactant effective to form a microemulsion; d. 9.5% to about 20% by weight of a solvent extender; and e. about 25% to about 60% by weight water; said composition being in the form of a microemulsion.
 3. The microemulsion cleaning composition according to claim 2 comprisinga. about 10% to about 20% by weight of a terpene compound; b. about 10% to about 20% by weight of a pyrrolidone compound; c. about 10% to about 15% by weight of a surfactant effective to form a microemulsion; d. about 10% to about 15% by weight of a solvent extender; and e. about 40% to about 50% by weight water; said composition being in the form of a microemulsion.
 4. The microemulsion cleaning composition according to claim 3, wherein the surfactant effective to form a microemulsion is selected from the group consisting of a nonionic surfactant and a cationic surfactant and mixtures thereof.
 5. The microemulsion cleaning composition according to claim 3, wherein the pyrrolidone compound is N-methylpyrrolidone.
 6. The microemulsion cleaning composition according to claim 2, wherein the solvent extender is selected from the group consisting of propylene glycol, hexylene glycol, and propylene glycol monomethyl ether and mixtures thereof.
 7. The microemulsion cleaning composition according to claim 2, wherein said composition has a flash point of at least about 105° F.
 8. The microemulsion cleaning composition according to claim 2, wherein said composition has a pH of about 2.0 to about 12.0.
 9. The microemulsion cleaning composition according to claim 2, wherein said composition has a pH of about 5.5 to about 8.0.
 10. The microemulsion cleaning composition according to claim 3, wherein said composition has a pH of about 6.0 to about 8.0.
 11. A microemulsion cleaning composition comprising:a. about 10% to about 20% by weight of a terpene compound; b. about 10% to about 20% by weight of N-methylpyrrolidone; c. about 10% to about 15% by weight of a surfactant effective to form a microemulsion, said surfactant being selected from the group consisting of a nonionic surfactant and a cationic surfactant and mixtures thereof; d. about 40% to about 50% by weight of water; and e. about 10% to about 15% by weight of a solvent extender selected from the group consisting of propylene glycol monomethyl ether and hexylene glycol and mixtures thereof; said composition being in the form of a microemulsion and having a flash point of at least 105 degrees F. and a pH of about 6.0 to about 8.0.
 12. A method for removing markings from a surface comprising:a. applying to a marking material on a substrate surface a microemulsion cleaning composition comprising:i. about 1% to about 60% by weight of a terpene compound; ii. about 1% to about 60 by weight of a pyrrolidone compound; iii. about 1% to about 35% by weight of a surfactant effective to form a microemulsion; iv. 9.5% to about 20% by weight of a solvent extender selected from the group consisting of small chain alcohols, alkylene carbonates, ethylene glycol, propylene glycol, butylene glycol, hexylene glycol, diethyleneglycolmonobutylether, diethyleneglycolmonoethylether, diethyleneglycolmonohexylether, diethyleneglycolmonomethylether, diethyleneglycolmonopropylether, dipropyleneglycolmonobutylether, dipropyleneglycolmonomethylether, dipropyleneglycolmonopropylether, ethoxypropyleneglycolmonobutylether, ethyleneglycolmonoethylether, ethyleneglycolmonohexylether, ethyleneglycolmonomethylether, ethyleneglycolmonopropylether, propyleneglycolmonobutylether, propyleneglycolmonomethylether, propyleneglycolmonopropylether, propyleneglycolmono-t-butylether, triethyleneglycolmonoethylether, triethyleneglycolmonomethylether, triethyleneglycolmonopropylether, and tripropyleneglycolmonomethylether; and v. at least about 20% by weight water, said composition being in the form of a microemulsion; b. contacting the marking material with said microemulsion composition for a period of time sufficient to solubilize said marking material; and c. removing from said surface said composition and said marking material with water.
 13. The method for removing markings from a surface according to claim 12, wherein the terpene compound ranges from about 5% to about 40% by weight, the pyrrolidone compound ranges from about 5% to about 40% by weight, the surfactant ranges from about 5% to about 20% by weight, the solvent extender ranges from 9.5% to about 15% by weight, and the water ranges from about 25% to about 60% by weight.
 14. The method for removing markings according to claim 12, wherein the terpene compound ranges from about 10% to about 20% by weight, the pyrrolidone compound ranges from about 10% to about 20% by weight, the surfactant ranges from about 10% to about 15% by weight, the solvent extender ranges from about 10% to about 15% by weight, and the water ranges from about 40% to about 50% by weight.
 15. The method for removing markings from a surface according to claim 14, wherein:a. The surfactant effective to form a microemulsion is selected from the group consisting of a nonionic surfactant and a cationic surfactant and mixtures thereof; b. The pyrrolidone compound is N-methylpyrrolidone; c. The solvent extender is selected from the group consisting of propylene glycol monomethyl ether and hexylene glycol and mixtures thereof; d. The cleaning composition has a flash point of at least about 105 degrees F.; and e. The cleaning composition has a pH of about 6.0 to about 8.0. 